1. Field of the Invention
The present invention relates to a multi-processor environment and more particularly to arrangements for transferring data between processes running in such environments.
2. Related Art
In complex systems, such as a telephone network for example, "intelligence" is present at many different points. A number of control processors provide the main functionality of the network, however, substantial processing capability also exists away from the central offices.
In particular, intelligent peripherals, that is peripherals including data processing decision-making capability will be present at the locations closer to the customer.
Facilities to be provided by an intelligent peripheral may not require the establishment of a physical connection through a particular network. Thus, some such intelligent peripherals may represent a node on several different operating networks. Further, where a network comprises a number of host computers, a process on one of the hosts may need to interact directly with a process on another.
Accordingly inter-process communications between processes running on different hosts must be reliable.
While permanent links between processes are reliable they represent substantial investment and are inflexible. Host computers are therefore more usually accessed through shared public networks such as the Internet.
The Internet provides a simple datagram facility to allow data to be transferred between host processes. The transfers use a simple user datagram protocol (UDP) provided by the Internet. Such a protocol is described, for example, by Postel, J in ARPANET Working Group Request for Comments number 768. While permitting a data transfer between processes the UDP datagram is not as reliable a method of transferring data on fixed or PSTN links.
Previous datagram transfer facilities including that known as TCP many result in break up of the data contained within the datagram since it does not preserve message boundaries and may take a considerable time to notify any failure of delivery, if indeed such notification is possible.